This invention relates to safety razors of the type that have a plurality of adjacently mounted blades permanently mounted in the razor head. More particularly, this invention relates to razor heads having a plurality of short blades having intrinsic fencing and lateral skin tensioning, mounted at a high slicing angle.
The advantages of using blades with a slicing rather than chopping motion have been known for hundreds, perhaps thousands of years. One has but to cut a loaf of bread to immediately realize that a slicing motion cuts cleaner and with less tearing. The most immediate advantage for the blade is the reduction of force that is required for cutting, reducing wear and tear on the cutting blade. For a shaver, it is perhaps more important that the cutting force applied to the follicles be reduced, producing a less painful shaving experience. While it has been possible for the shaver to use straight razors, as well as disposable razor cartridges, in such a way as to create an oblique or slicing angle, this has always been hazardous, as the blade that easily slices follicles also easily slices the epidermis. Several patents have resulted from attempts to safely apply the advantages of a slicing angle to shaving. Gordon, (U.S. Pat. No. 3,964,160) and Copelan, (U.S. Pat. No. 5,526,568) patented razors which made manual oblique shaving easier, that is, the wrist did not have to be held at an awkward angle to maintain the slicing angle, but both lacked the concomitant stability of a razor head perpendicularly oriented to the shaving direction. Copeland teaches that, to obtain the advantages of oblique shaving while avoiding cutting of the skin, the oblique angle of a useable razor head should be restricted to between 10 and 26 degrees, and preferably to an angle of 18 degrees. Razors featuring adjustable slicing angles, such as Gordon""s, have had an additional disadvantage, since the geometry of the razor head must be carefully balanced, and is unlikely to be optimum for variable slicing angles. Others have patented a variety of oblique arrangements, wherein a pair of blades are oriented in a xe2x80x9cVxe2x80x9d arrangement. Carroll (U.S. Pat. No. 1,241,921), Moody (U.S. Pat. No. 228,829), and Browning (U.S. Pat. No. 1,387,465) are typical of this approach, which suffers from excess stability. Because of the large footprint created by the two legs of the cutting zone, such a razor head has great difficulty in handling variations in facial geometry; a difficulty which only increases as the slicing angle, is increased. Savage (U.S. Pat. No. 4,663,843) patented a razor head using a conventional blade in tandem with blades angled at a slicing angle. He teaches that the slicing angle should lie between 15 and 30 degrees, in order to have some of the advantages of oblique cutting, while avoiding cutting of the skin. Savage does not appreciate the advantages arising from the use of intrinsic fencing, which would not only allow shaving at much higher slicing angles, but also make a tandem conventional blade unnecessary. Hadjopoulos (U.S. Pat. No. 2,043,998) patented a razor with a serrated edge. This razor suffers from a number of deficiencies. First, the continuity of the cutting edge is broken by the finger guards, resulting in an incomplete shave; second, the shaving angle must be zero if all of the cutting edges are to contact the skin; and third, in moving the razor in the trim direction, the blades are shadowed by the cap, preventing a clean trim line from being produced. It can also be expected that skin flow control would be poor, as thin skin would tend to bunch between the facing edges of each serration, resulting in an uneven shave, as well as cutting of the epidermis. The patent art is crowded with examples of razors that attempt to employ angled cutting edges, but until now, none have appreciated the combination of characteristics necessary for taking full advantage of a high slicing angle.
Tensioning of the skin in order to control the flow of skin under the cutting edge is an important consideration. Tensioning is often accomplished by providing grooves built into the leading guard, in order to stretch the skin prior to contact with the cutting edges, as taught in U.S. Pat. No. 4,247,982 to Booth, et al. In U.S. Pat. No. 3,909,939, Dootson teaches alternating slanted grooves in the leading guard. Similarly, in U.S. Pat. No. 3,138,865, Meyer claims a safety razor having skin stretching means comprising triangular serrations in the leading guard. These serrations may be flexible, as in U.S. Pat. No. 5,689,883, to Oritiz, and may also be employed in side guards as in U.S. Pat. No. 5,546,660, to Burout. Another means of tensioning the skin prior to the cutting edges comprised rollers as in U.S. Pat. No. 2,766,521 to Benvenuti, and as in U.S. Pat. No. 1,651,917, to Connolly. All of these tensioning means work outside of the cutting zone. It is preferable however, to tension the skin closely as possible to the cutting zone, and it would be most preferable to tension the skin within the cutting zone itself, and to provide for lateral tensioning.
Fencing of razor blades is known. Dickenson, in U.S. Pat. No. 1,035,548, teaches the use of wire wrapping of the blade edges, an approach that has been used by several others, such as Iten, in U.S. Pat. No. 3,505,734, and Michelson, in U.S. Pat. No. 3,750,285. Similarly, Ferrara, in U.S. Pat. No. 3,263,330, discloses a fencing arrangement wherein the blade edge is wrapped with a flexible perforated sheet, and Auton, in U.S. Pat. No. 4,252,837, claims a blade fenced with a vacuum deposited intermittent coating. Galligan et al., in U.S. Pat. No. 4,914,817, teaches the use of tape having parallel riblets covering parts of the blade edges. None have previously appreciated the advantages accruing from intrinsically fenced blades. All the United States patents cited in the Specification are hereby fully incorporated by reference.
Accordingly, I claim the following as objects and advantages of the invention: to provide a razor head having intrinsically fenced cutting means oriented at a high shearing angle which is capable of producing a smooth, safe shave with reduced pulling of follicles, to enhance the life of razor cutting means, to provide a clean trim line, to provide bi-directional skin tensioning within the cutting zone, to provide cutting edges with varying shaving and slicing angles, to provide channels for improved flow of shaving debris, and to provide improved interaction of shaving lubricant with the cutting edges.